Testing and/or debugging an integrated circuit, such as for example a terminal processor, or software executed on a system comprising an integrated circuit is very difficult using only ordinary output devices, such as displays or serial interfaces, connected to the integrated circuit.
Therefore integrated circuits sometimes have dedicated testing and/or debugging interfaces. They are frequently used during the development phase of an integrated circuit or software to be executed on a system comprising an integrated circuit. When a system comprising an integrated circuit matures and is put inside its actual mechanics, these dedicated testing and/or debugging interfaces are commonly covered, thus complicating access to the testing and/or debugging interfaces. However, it is sometimes necessary to still access these dedicated testing and/or debugging interfaces, for example if some bug or fail is discovered or if the system is to be tested under authentic conditions of use.